Aging is characterized by a paradox between mild to serious health-related deterioration including cognitive decline and neurodegenerative disorders and improved socioemotional functioning and well-being. This latter finding is characterized by subjective reports of increased general life satisfaction and psychological well-being in the elderly, decline in reported negative mood states, particularly among women, as good or improved positive moods compared to young adults and greater involvement in close social relationships, especially among females and kin. One of the primary theories put forth over the last few decades to explain this apparent paradox is the Socioemotional Selectivity Theory (SST). According to this theory, reported emotional satisfaction among the aged is not simply due to lower expectations for social relationships or day- to-day mood quality, but to an active and selective management of social relationships and activities to maximize positive emotional interactions and minimize negative experiences. This project will use the SST to guide studies of age-related changes in social cognition among three species of female primates. This project will address 3 Specific Aims. First, we will examine age and species differences in processing familiar vs. unfamiliar conspecific's faces and facial expressions. Second, we will examine age and species differences in the relationship between emotion and attention using reaction time measures in an emotional priming task. Finally, we will use both longitudinal and cross-sectional archival data from nonhuman primates to address whether the quality of social relationships changes with aging such that older females selectively associate with close friends and relatives compared to novel or less familiar individuals. Such a broad comparative study focusing on females will provide important insights into the unique aspects of human aging, the brain mechanisms that are most affected by age-related changes in cognition and emotion, and provide a means for understanding the impact these changes may have on the social organization of related species, which is largely influenced by females.